Summarising birth risk factors for autism

Hot on the heels of the various evidence published last week on the rise and rise of variable gene-environment interactions in relation to autism aetiology, an entry on the Autism Speaks blog directed me to a study published in the Pediatrics today which takes an overview look at the collected data on birth factors in relation to risk of developing autism. The abstract to the paper can be found here.

Based on a meta-analysis of several studies looking at various perinatal and neonatal risk factors analysed in connection to autism, several issues are suggested to be potentially related by Gardener and colleagues, although like many things about autism, no one factor or pattern of factors seems to show a universal connection.

So, issues such as umbilical cord 'complications' (I assume this means things like knots and/or being wrapped around baby's head), low birth weight and small for dates are a few of the risks which seem to show some possible connection. Others which have already come up on this blog in one shape or form include: hyperbilirubinemia, neonatal anaemia, feeding difficulties, and being a summer birth. I note also a possible connection with blood or rhesus incompatibility which is something I perhaps will go into in a future entry. There were a few other conditions not found to be associated with any increased risk including head circumference and prematurity. I was a bit taken aback by prematurity not showing association when the data were joined. Having said that, studies like this one have perhaps indicated that such issues might be more related to any co-morbid cognitive problems attached to the autism diagnosis. The head circumference factor is something that is due to be discussed in a separate post in the coming weeks.

I don't want to jump on to any bandwagon with these findings because, as the authors note, they were often comparing oranges and apples with the array of research reviewed. I do however think that this paper provides some important data when starting to look at both 'risk' factors in developing autism and possibly mechanisms; building on what is known about some of the birth factors listed and the risk of other physical and behavioural developmental conditions outside of autism.